20th International Forgemasters Meeting - IFM 2017

3.5%NiCrMoV steel has been widely used for generator rotor forgings for the purpose of obtaining high strength, toughness and magnetic permeability. Although the added alloy elements are important to achieve specified mechanical properties, reducing the amount of alloy elements is also important to contribute to natural resource savings and cost savings. In this study, the effects of Ni and Cr on mechanical properties of NiCrMoV steel were investigated. As the result, a new lower Ni steel has been developed with mechanical properties equivalent to 3.5%NiCrMoV steel, which has been used for generator rotor forgings for several decades. Developed steel has been applied for commercial generator rotor forgings, and the mechanical properties have been evaluated through joint research with GE Power. At present, the expansion of its applications is progressing.